package com.firepongo.chaos.app.utils;

/**
 * @author G.G
 * @date 2020/9/20 16:28
 */
public class DistanceUtil {
    //赤道半径
    private static final  double EARTH_RADIUS = 6378137;
    private static double rad(double d){
        return d * Math.PI / 180.0;
    }
    public static double GetDistance(double lon1,double lat1,double lon2, double lat2) {
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);
        double a = radLat1 - radLat2;
        double b = rad(lon1) - rad(lon2);
        double s = 2 *Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2)+Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
        s = s * EARTH_RADIUS;
        //单位米
        return s;
    }
}
